Akai X-165D

Vil.
AMPLIFIER
ADJUSTMENT
a)
b)
Cc)
d)
Bias Head 102 ~50 0
.
RECORDING
BIAS
FREQUENCY
ADJUSTMENT
Put
a
resistor
(10
Q
or
50
2)
in
series
with
the
bias
head,
and
connect
the
signal
from
the
resistor
to
the
vertical
input
of
the
oscilloscope.
Feed
a
sine
wave
signal
from
an
Audio
Frequency
Oscillator
to
the
Horizontal
Input
of
the
Oscil-
loscope
and
tune
the
dial
of
the
Audio
Oscillator
until
the
Oscilloscope
displays
a
circular
or
linear
pattern.
|
A
reading
of
60
kHz
+
5
kHz
indicates
that
the
Recording
Bias
Frequency
is
correct.
If
incorrect,
it
can
be
adjusted
by
adjusting
the
value
of
condenser
C-402
(3000
pF).
OSCILLOSCOPE
Ze:
a)
Oscillator Circuit
AUDIO FREQUENCY
OSCILLATOR
Fig. |
¢
x
RECORDING BIAS VOLTAGE
ADJUSTMENT
Connect
a
V.T.V.M.
to
the
bias
head
and
fix
the
recording
bias
voltage
by
adjusting
the
V.A.C
in
the
bias
oscillator
circuit
(located
near
the
head
as-
sembly)
until
its
reading
becomes
equal
to
the
bias
voltage
stamped
on
the
back
of
the
head
assembly.
Normal
bias
voltage
is
between
60
V
and
70
V,
while
acceptable
terminal
voltage
of
the
erase
head
is
between
12
V
and
18
V.
13
GA A tpl Me SAE pln ah CE Aa ID